Testes

Causes

In the first several weeks after the egg is fertilized, the embryo develops early sex organs. In the male, if the early testes fail to develop before 8 weeks into the pregnancy, the baby will have female genitals.

If the testes are lost between 8 and 10 weeks, the baby will be born with ambiguous genitalia. This means the child will have parts of both male and female genitals.

Ambiguous genitalia

Ambiguous genitalia is a birth defect where the outer genitals do not have the typical appearance of either a boy or a girl.

However, if the testes are lost after the time when the male genitals differentiate (between 12 and 14 weeks), the baby will have normal male genitals (penis and scrotum), but no testes. This is known as congenital anorchia, or the "vanishing testes syndrome."

The cause is unknown, but in some cases there are genetic factors.

Symptoms

Normal outside genitals before puberty

Failure to start puberty at the correct time and lack of secondary sex characteristics (penis and pubic hair growth, deepening of the voice, and increase in muscle mass)